Nearly 125 years ago, the newly constructed Washington Monument was topped with a pyramid-shaped 100-ounce, 9" high block of cast aluminum--that cost $225, an expensive price then, more costly than gold, silver, or platinum.
But some comparisons are in order:
I wanted to figure an accurate comparison, so I used the daily wage for a worker. Historians say the average worker in 1884 made $1 a day (10 hours). Today, the average worker putting in 10 hours would earn about $70. So a 70-fold increase of $225, or $15,750, would be the pyramid's cost in current dollars.
One hundred ounces (6.251b) of aluminum today at $1.23 a pound comes to $7.71. So what was an exorbitant expense in 1884 costs less than $8 now.
This disparity has been due to the use of the 1886 Hall-Heroult electrolytic aluminum process, which permanently ended such high prices for the metal.
The process involves dissolving alumina in molten cryolite. Then the solution is electrolyzed, and pure aluminium metal forms.
More aluminum is produced today than all other nonferrous metals combined.
I mention this as an outstanding example how technology came into play and created a lower cost for the metal. As the price of materials rises steadily today, it's refreshing to look back and see from where we have come.
Why the cost
A large part of the reason aluminum had cost so much was because a foundry had to use the highest quality aluminum oxide available--which in the 19th century was corundum. The purest form of corundum is the crystalline form, which includes rubies and sapphires. Many of these stones were being mined in the streambeds and mountainsides of the Carolinas, with most from Macon County, NC.
In the sodium reduction process in use at the time, the crushed corundum first had to be converted chemically into aluminum chloride and then reduced with sodium to form salt and metallic aluminum. Sodium itself was expensive, not to mention that the metallic form was difficult to work with; it would explode when exposed to air.
The actual smelting of the corundum ore and casting of the aluminum pyramid was done by a noted metallurgist of the time, William Frishmuth, in Philadelphia, PA.
The pyramid was inscribed with the names of dignitaries involved and was put in place on...